The present invention relates to processes and equipment for controlling and/or adjusting the temperature of equipment used in the manufacture of a film, web or other articles that are typically manufactured in a high speed, continuous manner.
During manufacturing processes, and more typically during high speed manufacturing processes, rolls and/or belts are often used to guide articles or materials and/or to perform certain operations that can affect the properties of the materials or articles being manufactured. For example, rolls and/or belts may be used to calender, emboss, heat, cool, tension, direct, apply glue, ink or other substances, etc. to materials or articles during manufacturing or converting processes. Typically, when rolls or belts are used in conjunction with the manufacture or converting of materials or articles in a continuous process, the material or article is in contact with the roll throughout only a portion of the roll""s rotation or the belt through only a portion of its path. For certain operations, it may be desirable for the material or articles being processed to reach or maintain a certain temperature range while in contact the roll through one portion of its rotation (or in the use of a belt, a portion of its path) and a different temperature when in contact with the roll through a different portion of its rotation. Alternatively, it may be desirable for one or more of the rolls and/or belts to be heated or cooled to a certain temperature range through a certain portion of its rotation or path and heated or cooled to another temperature range along a different portion of its rotation or path. However, controlling the temperature of the material being processed or the rolls and/or belts themselves can be very complicated and costly and is very difficult to achieve with current technology, especially at high speeds.
xe2x80x9cCurrent techniques for cooling rolls used during manufacture include passing fluid through the roll to control the temperature of the roll, applying air, steam or water to the circumference of the roll and contacting an idler roll to the manufacturing roll to add or remove heat from the surface of the manufacturing roll. Examples of such methods are disclosed in U.S. Pat. Nos. 4,805,554 issued to McIntyre; 5,058,496 issued to Wittkopf; 5,212,975 issued to Ginzburg; 5,799,411 issued to Scheil and 6,256,903 issued to Rudd. However, techniques focusing on convective cooling has significant shortcomings in that it cannot transfer heat as efficiently as conduction, thereby limiting production rates. Further, the use of fugitive fluid for heating or cooling is often undesirable due to the inherent recovery and hygiene difficulties. With respect to the use of a roll contacting another roll to provide heat exchange, such methods are relatively inefficient because duration of the heating or cooling of the circumference of the roll being heated or cooled is limited by the nip between the rolls. The present invention overcomes these disadvantages by providing the capability to conductively chill a greater portion of a roll""s surface. Furthermore, this invention provides the capability to provide supplemental vacuum forces to assist in the removal of the web/adhesive structure from the roll""s surface coincident with the temperature reduction.xe2x80x9d
Accordingly, it would be desirable to provide a cost effective method and/or apparatus for controlling the surface temperature of a belt as it moves along its path. It would also be desirable to provide a cost effective method and/or apparatus for controlling the surface temperature of a roll as it rotates about its axis. Further, it would be desirable to provide an apparatus and/or method of controlling the temperature of a material and/or article being manufactured or converted using a roll or belt, wherein the temperature of the material and/or article is controlled while passing through a given portion of the roll""s rotation about its axis or the belt""s movement along its path. Further, it would be desirable to have an apparatus and/or method of providing zone temperature control of a roll or belt or a material being processed in an operation employing rolls or belts that can be used with or in place of current roll or belt technology. It would also be desirable to provide an improved process and apparatus for providing zone temperature control of a roll, belt or a material being processed in an operation employing rolls or belts that can be employed at high speeds and/or in continuous operations.
All documents cited herein are, in relevant part, incorporated herein by reference. The citation of any document is not to be construed as an admission that it is prior art with respect to the present invention.
The method and apparatus of the present invention provide a unique solution to the problems of the prior art by using a belt to modify the temperature of a manufacturing roll. For example, the method and apparatus of the present invention may be used to zone control the temperature of a rotating roll. In one embodiment, the apparatus may include a roll having a surface at a first temperature, the roll capable of rotating about an axis; and a belt disposed adjacent at least a portion of the surface of the roll and contacting the surface of the roll in a contact region, the belt having a second temperature that is different from the first temperature, wherein the belt affects a temperature change in at least a portion of the surface of the roll in the contact region as the roll is rotated.
One method for zone controlling the temperature of a rotating roll according to the present invention includes the following steps: (a) providing a roll having an axis and a surface at a first temperature; (b) providing a belt disposed adjacent at least a portion of the surface of the roll; (c) heating or cooling the belt to a second temperature that is different from the first temperature; (d) directly or indirectly contacting the belt with the surface of the roll in a contact region, (e) rotating the roll while in contact with the belt such that the belt affects a temperature change in at least a portion of the surface of the roll in the contact region as the roll is rotated.
Alternative methods and apparatuses to perform the methods are contemplated and described in more detail in the following sections of this specification.